1. Field
Embodiments of the present invention relate to a data storage device and an operating method thereof, and more particularly, to a data storage device including two or more types of memory devices which classifies properties of data and selectively stores the data in the memory devices according to property, and a method of operating the same.
2. Description of the Related Art
Recently, much attention has been paid to a solid state drive (SSD) that includes a flash memory device as a data storage device to replace a hard disk drive.
Basically, a flash memory device cannot overwrite data. Therefore, in order to write new data at a physical location where data already exists, the existing data must be erased before the new data is written. In general, since a unit for a data erase operation (for example, a block including a plurality of pages) is larger than a unit for a data write operation (for example, a page), valid pages and invalid pages may coexist in one block. The valid pages represent pages storing valid data, and the invalid pages represent pages storing invalid data that is to be erased.
If the number of blocks including fewer valid pages than invalid pages increases, an available storage space of the flash memory device may decrease. Thus, in order to prevent such a problem, a garbage collection operation is performed on the blocks.
Flash memory devices include single-level-cell (SLC) memory devices and multi-level-cell (MLC) memory devices. An SLC memory device includes a plurality of SLCs each storing one bit, and a MLC memory device includes a plurality of MLCs each storing multiple bits. SLC memory devices have a higher operating speed than MLC memory devices, but have a higher price than MLC memory devices.
Therefore, there is a need for a data storage device that minimizes the disadvantages without compromising the advantages offered by both a high-speed memory device, such as an SLC memory device, and a high-capacity memory device, such as an MLC memory device.